[green] Make release test Git identity hermetic

Signed-off-by: Viwat Vchirawongkwin <viwat.v@chula.ac.th>

Author: yyods

tests/firmware_tests/host/test_release_hardening.py

@@ -1329,6 +1329,10 @@ def test_dirty_or_drifted_checkout_cannot_validate_old_build_identity(self):
                         _git(
                             checkout,
                             "-c",
+                            "user.name=PyBLE Test",
+                            "-c",
+                            "user.email=test@pyble.invalid",
+                            "-c",
                             "commit.gpgsign=false",
                             "commit",
                             "-q",